This invention relates to Group VIB metal sulfide slurry catalysts used for the catalytic hydroprocessing of heavy hydrocarbonaceous oils including crude oils, heavy distillates, such as FCC decanted oils and lubricating oils. The catalysts can also be used for the hydroprocessing of shale oils, oils from tar sands and coal liquids.
The Group VIB metal sulfide slurry catalyst particles of this invention can exist as a substantially homogeneous dispersion in a water/oil mixture of very small particles made up of extremely small crystallites. Examples of suitable Group VIB metals include molybdenum and tungsten. Each of these metals can be present in approximately the disulfide form. However, the apparent atomic ratio of sulfur to metal can be greater or less than 2. The preferable metal is molybdenum and the molybdenum catalyst will be particularly described herein. The catalyst is probably structured molecularly as platelets formed from hexagonal sheets of molybdenum or tungsten atoms separated by two hexagonal layers of sulfur atoms with activity sites concentrated at the edge of each basal plane of the molybdenum or tungsten atoms.
We have found that the activity of the catalyst of this invention can be defined by the pore volume expressed as cubic centimeters per gram (cc/g) based on pores in the 10 to 300 Angstroms (.ANG.) radius size range. The catalyst of this invention has at least 0.1 cc/g pore volume in pores between 10 and 300.ANG. in radius; preferably at least 0.15 and most preferably at least 0.2 cc/g in pores having a radius between 10 and 300.ANG.. Catalysts of this invention can have a pore volume in pores having a radius between 10 and 300.ANG. of between 0.15 or 0.2 to 1 cc/g. Good activity is obtained in the range 0.2 to 0.4 cc/g while preferably activity is obtained by extending the upper end of the range to 1 cc/g, or higher.
We have found that the catalyst of this invention can also be defined by its surface area expressed as square meters per gram (m.sup.2 /g). Good activity is achieved with a surface area of at least 20 or 25 m.sup.2 /g. Surface areas between 25 and 75 or 100 m.sup.2 /g give good catalyst activities while surface areas above 75 or 100 cc/g and up to 400 cc/g, or higher, give preferable activity.
The following equations are used to calculate the pore volume and surface area of the catalysts on a carbon-free basis.